The invention relates to erection mechanisms for packing cases.
In situations where packing cases are to be filled with product at the end of a production line, it is normal practice to have a supply of folded flat packing cases which are erected immediately prior to being filled. The packing cases may be used once only or may be re-usable after product in them has been delivered to its destination. In either situation, the cases are in a folded condition for transport and remain in the folded condition for as long as possible to save space in the packing area.
The kind of case with which the invention is particularly concerned is a foldable packing case having two major and two minor sides effectively hinged together enabling the case to be folded from a flat condition via a parallelogram configuration to a rectangular configuration. The case has two major base flaps and two minor base flaps, each effectively hinged to the bottom edge of a corresponding side with the flaps being shaped for mutual interlocking and being foldable in the sequence of first major flap, both minor flaps and then the second major flap into positions where they interlock and form a base in a base plane generally conforming to the plane including the lower edges of the sides, the second major flap temporarily being folded beyond the base plane to cause said interlocking.
Packing cases of this kind are normally erected by hand by an operative and are then loaded manually into a machine, either directly into a loading station or into a waiting station where they are fed by the machine into the loading station as required.
Automatic case erectors are known but in the past when automatic case erection has been required, base flaps have been secured together to form a base by means other than mutual interlocking, eg. by an adhesive. When the base is built up in this way, it becomes impractical to collapse the case and re-erect it later so such cases are not generally re-usable in a regular production environment.
An objective of the present invention is to provide a machine for automatically erecting packing cases of the kind in which the bases are formed by mutually interlocking flaps.